Lease Extension Calculator

Last updated January 2019

This calculator will give you an estimate of the premium for a lease extension for a flat, but it cannot give you the actual costs. In considering the likely total cost you should also bear in mind the leaseholder's liability for the landlord's costs. The eventual cost of the new lease will be the premium plus both your own and the landlord's "reasonable" professional costs. Stamp duty is also applicable above £125,000. These costs could be significant so be sure to get estimates from the professionals involved (likely to be at least solicitors and surveyors) before you decide to proceed.

The estimate is likely to be helpful where there is no evidence of comparable transactions. The calculator is for initial consideration purposes only. You should not take any action without seeking formal professional advice first. Therefore, you should not use this information in tribunal or court proceedings and neither should you take any other action based on this information without first getting professional advice. Although we offer an advice guide, Lease extension - Valuation about valuations under the Leasehold Reform, Housing and Urban Development Act 1993 (as amended), you should remember that the law and the way property is valued can change over time and that local evidence can vary.

The current priority, when assessing the short lease value, is evidence of similar flats usually in the same block or estate. This requires extensive local knowledge beyond the scope of this national calculator. Where there is no clear evidence of short lease sale transactions, a graph approach is likely to be adopted but should produce similar results to this estimate.

Please note that this calculator cannot do calculations for leases with less than 50 years remaining (40 years for flats in Central London).

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